Examples with QueryTransformer org.hibernate.sql.ast.tree.expression.QueryTransformer used on opensource projects

Example 1 with QueryTransformer

use of org.hibernate.sql.ast.tree.expression.QueryTransformer in project hibernate-orm by hibernate.

the class BaseSqmToSqlAstConverter method visitQuerySpec.

@Override
public QuerySpec visitQuerySpec(SqmQuerySpec<?> sqmQuerySpec) {
    final boolean topLevel = getProcessingStateStack().isEmpty();
    final QuerySpec sqlQuerySpec = new QuerySpec(topLevel, sqmQuerySpec.getFromClause().getNumberOfRoots());
    final SqmSelectClause selectClause = sqmQuerySpec.getSelectClause();
    final Predicate originalAdditionalRestrictions = additionalRestrictions;
    additionalRestrictions = null;
    final boolean trackAliasedNodePositions;
    if (trackSelectionsForGroup) {
        trackAliasedNodePositions = true;
    } else if (sqmQuerySpec.getOrderByClause() != null && sqmQuerySpec.getOrderByClause().hasPositionalSortItem()) {
        trackAliasedNodePositions = true;
    } else if (sqmQuerySpec.hasPositionalGroupItem()) {
        trackAliasedNodePositions = true;
    } else {
        // Since JPA Criteria queries can use the same expression object in order or group by items,
        // we need to track the positions to be able to replace the expression in the items with alias references
        // Also see #resolveGroupOrOrderByExpression for more details
        trackAliasedNodePositions = statement.getQuerySource() == SqmQuerySource.CRITERIA && (sqmQuerySpec.getOrderByClause() != null || !sqmQuerySpec.getGroupByClauseExpressions().isEmpty());
    }
    final SqlAstProcessingState processingState;
    if (trackAliasedNodePositions) {
        processingState = new SqlAstQueryPartProcessingStateImpl(sqlQuerySpec, getCurrentProcessingState(), this, r -> new SqmAliasedNodePositionTracker(r, selectClause.getSelections()), currentClauseStack::getCurrent, deduplicateSelectionItems);
    } else {
        processingState = new SqlAstQueryPartProcessingStateImpl(sqlQuerySpec, getCurrentProcessingState(), this, currentClauseStack::getCurrent, deduplicateSelectionItems);
    }
    final SqmQueryPart<?> sqmQueryPart = currentSqmQueryPart;
    final boolean originalDeduplicateSelectionItems = deduplicateSelectionItems;
    currentSqmQueryPart = sqmQuerySpec;
    // In sub-queries, we can never deduplicate the selection items as that might change semantics
    deduplicateSelectionItems = false;
    pushProcessingState(processingState);
    queryTransformers.push(new ArrayList<>());
    try {
        // we want to visit the from-clause first
        visitFromClause(sqmQuerySpec.getFromClause());
        visitSelectClause(selectClause);
        final SqmWhereClause whereClause = sqmQuerySpec.getWhereClause();
        if (whereClause != null) {
            sqlQuerySpec.applyPredicate(visitWhereClause(whereClause.getPredicate()));
        }
        sqlQuerySpec.setGroupByClauseExpressions(visitGroupByClause(sqmQuerySpec.getGroupByClauseExpressions()));
        if (sqmQuerySpec.getHavingClausePredicate() != null) {
            sqlQuerySpec.setHavingClauseRestrictions(visitHavingClause(sqmQuerySpec.getHavingClausePredicate()));
        }
        visitOrderByOffsetAndFetch(sqmQuerySpec, sqlQuerySpec);
        if (topLevel && statement instanceof SqmSelectStatement<?>) {
            if (orderByFragments != null) {
                orderByFragments.forEach(entry -> entry.getKey().apply(sqlQuerySpec, entry.getValue(), this));
                orderByFragments = null;
            }
            applyCollectionFilterPredicates(sqlQuerySpec);
        }
        QuerySpec finalQuerySpec = sqlQuerySpec;
        for (QueryTransformer transformer : queryTransformers.getCurrent()) {
            finalQuerySpec = transformer.transform(cteContainer, finalQuerySpec, this);
        }
        return finalQuerySpec;
    } finally {
        if (additionalRestrictions != null) {
            sqlQuerySpec.applyPredicate(additionalRestrictions);
        }
        additionalRestrictions = originalAdditionalRestrictions;
        popProcessingStateStack();
        queryTransformers.pop();
        currentSqmQueryPart = sqmQueryPart;
        deduplicateSelectionItems = originalDeduplicateSelectionItems;
    }
}